A number of assemblies and assembly methods have been proposed for mounting electrical components to, for example, the chassis of electrical devices. There are, for example, the devices and methods illustrated and described in U.S. Pat. Nos. 4,193,444; 4,204,248; 4,288,839; 4,509,839; 4,707,726; 5,060,112; 5,122,480; 5,309,979; 5,321,582; 5,327,324; 5,363,552; 5,369,879; and, 5,812,376, to identify but a few. This listing is not intended as a representation that a thorough search of the prior art has been conducted or that no more pertinent art than that listed above exists, and no such representation should be inferred.
Power semiconductive devices, such as bipolar power transistors, typically are mounted on heat sinks which conduct away from the active regions of such devices heat evolved by the active regions of such devices during their operation. Examples include power transistors in the output stages of audio amplifiers operating in classes A and AB. These devices are required to be mounted in such ways as to be capable of dissipating powers of the same order of magnitude as is delivered to the loads, typically the voice coils of loudspeakers, they are driving. These powers must be dissipated in order to prevent damage to the devices themselves. Usually, this is accomplished by mounting such devices on heat sinks, massive structures of highly heat conductive material, for example, aluminum, mounted to, or formed as part of, the chassis of the electrical equipment of which the power semiconductive devices are components.
In the past, threaded fasteners have routinely been used to mount such power semiconductive devices to such heat sinks. This is problematic for a number of reasons, not the least of which is that the headers of such devices, which are, by design, frequently maintained at the same electrical potentials as one of the terminals, for example, the collector, of the devices, are also the components of the devices through which pass the threaded fasteners used to attach the devices to the heat sinks. This requires that some care be exercised in mounting the devices to the heat sinks in ways which will promote the flow of heat from the devices, but maintain electrical insulation of the devices from the heat sinks. Alternatively, the chassis of such electrical equipment must be designed in such a way as to accommodate heat sinks at the electrical potential of one of the terminals of the electrical devices mounted on them. This, in turn, may require multiple heat sinks, each electrically insulated not only from other heat sinks on the same electrical equipment but also typically from the chassis of the electrical equipment itself.